The disclosure relates to a motor.
Generally, a motor used to generate a rotational driving force is classified into a surface-mounted permanent magnet motor and a buried permanent magnet motor according to a coupling structure of a permanent magnet installed at a rotor core.
FIG. 1 illustrates a stator core and a rotor core of a surface-mounted permanent magnet motor according to the related art.
As shown in FIG. 1, the surface-mounted permanent magnet motor 10 according to the related art includes a stator 1 having a substantially cylindrical shape and a rotor 3 rotatably received inside the stator 1.
The rotor is made by stacking a plurality of magnetic steel plates having the same shape to form the rotor core 3. A rotation shaft hole is axially formed at a central portion of the rotor core 3 so that a rotation shaft 5 is press-fitted in the rotation shaft hole to rotate together with the rotor.
Holes are circumferentially formed around the central portion of the rotor core 3 so that a plurality of permanent magnets 6 are inserted or attached into the holes, respectively.
A repulsive force is generated between adjacent permanent magnets 6. Meanwhile, the stator 1 includes a ring type core, a plurality of teeth circumferentially spaced apart from each other at an inner peripheral surface of the ring type core while interposing a predetermined slot therebetween, and coils 2 wound around the teeth and connected to an external power supply.
A non-magnetic member 4 is formed between the rotation shaft 5 and the rotor to concentrate a magnetic flux.
In this case, as an area of the permanent magnet is increased in an axial direction, the rotor core 3 becomes narrower. Accordingly, there are limitations to increase the area of the permanent magnet 6 in a central direction to ensure a sufficient magnetic flux.